And head over to the National Arboretum at 24th & R Streets NE. The arboretum has cherry trees, azaleas, and many other blooming beauties. Like the tidal basin, the arboretum is right at the river. That would be the Anacostia River.
Don't miss the Koi fish outside the administrative building, which visitors are sometimes allowed to feed.
The arboretum is also accessible by Metrobus from Union Station. The arboretum is over 400 acres, however, they do offer tram tours.